Research On Dynamic Characteristics Of Prestressed Concrete Truss Beam Bridge

With the rapid development of ecomony, the bridge construction in china has been rapid development, structural forms of bridge has gradually diversified, large-scale and light. Prestressed concrete truss beam bridge can give full play to the characteristics of high strength material, promoting the structure light, has the very good crossing ability, and can effectively avoid the concrete cracking at the same time. In addition, it also has the advantage of high rigidity, good durability, light weight, saving advantages, such as steel and cement, beautiful modelling, combined with the structure clear and the characteristics of simple structure, small expansion joint, in the present bridge construction has been more and more popularization and use. Based on its characteristics such as light weight, making it vulnerable to wind load, the influence of vehicle load, seismic load and dynamic load, so the dynamic characteristics of the bridge research is our common concern.Bridge structure fundamental frequency reflect the relationship between the structure and impact coefficient of bridge, so accurate fundamental frequency calculation directly affect the size of the impact factor. The specification clearly stipulated in the provisions, the natural vibration frequency of the bridge appropriate USES finite element method. For some of the conventional structure, the specification provides formulas for calculating the fundamental frequency, but the fundamental frequency calculation formula of prestressed concrete truss beam bridge specification is still lack of both at home and abroad, it is necessary to study the fundamental frequency calculation formula of prestressed concrete truss beam bridge.According to the above problem, this paper mainly do the following work:(1)Using finite element software Midas/Civil, prestressed concrete truss bridge with different span, width, chord structure design parameters, such as stiffness, CHS stiffness as the breakthrough point, to establish the model and calculating the structural fundamental frequency.(2) The effect of various parameters on the structural fundamental frequency, determine the sensitive parameters.(3) According to the effect of sensitive parameters on the structural fundamental frequency, fitting of fundamental frequency calculation formula of prestressed truss girder bridge.(4) Measured the fundamental frequency of Wu Jian bridge and Yang Shi bridge, the measured values and the formula to calculate value close to, this paper puts forward the fundamental frequency calculation formula of prestressed truss girder bridge can be used for reference in the engineering design.